Air engine



Feb. 14, 1939. R. D. CONKLIN E1- AL 2,147,150

AIR ENGINE Original Filed Aug. 5, 1936 3 Sheets-Sheet 1 LE SE an 2 mm mm QINVENTOR ROSCOE D. CONKLIN PARIS R.

FOR IAN A RNEYS F s RL D. CQNKUN ET'AL 2,147,150

I AIR ENGINE Original Fild Aug. 5, 1936 3 Sheets-Sheet 3 H .5 i a; .7

INVENTOR ROSCOE D. CONKLIN 1 .41518 R. FORNAN ATTORNEYS- Patented Feb. 14, 1939 v I 2,147 15 Am ENGiNE V I Roscoe D, Conklinand Paris R FormamRahway, N. J., assignors to National Pneumatic Company, New York, N. Y., a corporation of West Virginia Original application August 5,- 1936, Serial No." 94,364,1iow Patent No. 2,089,932, dated August 17,1937; Divided: and this application January 13,- 1937, Serial No. 120,371 8 claims. (01. 12144)? This invention relates to pressure fluid-oper- Figure 6 isa cross-sectional view taken on the ated: engines of the reversible-type which can' be li-nefii of Figure; v set to automatically'return: to its'i-niti'al-position Figure '7 isa side-elevationalview with a poraiter operating. therefrom to the end of itsstroke tion insectionof one of the valve parts; 5 onendirection.

. Figure 8 isaright hand elevational view there- 5 'An object of this invention is; to-provide in of; and

simplified: form a;- pressure fluid operated engine FigureiQ is a left hand 'elevational view of anwhich in normal operation is alwaysconnected to other part of the valve mechanism. the" pressure fluid source and. whichhas its con- 1 I he engineisshown comprising a cylinder 6 10 trolling valve incorporated intothe structure of closed at one end by a specially formed cap 9, l0 thep'lston and which is provided: with an exterand atthe other end bymeans of a differently naliy projecting operating member; termedcap H1. At- H is the long piston rod "A further' object is to provide a positionable whieh-- passes through the" cap l0 and is conrnemb'e'r which: in one position cooperates with .ne'ctedat the inner end to a particular form of the valves on the pistomto' causethe piston to piston valve structure:- The outer end I2- is of 5 return to initial position at theen'dof its stroke reduced diameter and passes through a hole in from that position; but when the positionable a-bracket Me, The reduced end H of the piston member ismovedso asnot to cooperate with the rod, which projects through the bracket I4, is valves" the piston remains atthe end ofits: stroke provided, as isclear fromFig. 1 with a threaded from: its initial position, collar l3 which is locked thereon by means of a "20 The inventionincludes-many additional objects lock nut B Rigidly secured to the bracket l4 which are successfully secured by- 'meansoi the is an arm -ll which projects across the endof constmction herein' disclosed" and which Will be the pistonrodgso as to be positioned to engage a apparent from the following description. free longitudinally slidablerod [9- which lies in 26 This invention resides substantially'in the comthe centralbore extending. all the way through bination, construction,arrangement and relative the piston rod. Interposedbetween the shoulder location of parts; all? as will be described in greatonthe pistonrod and the bracket [4 is a spring er detail in the following specification. .16 which will be referred to later.

This application is a division: of: our co-pend The cap-I0 is providedwith a threaded passage 30 ihg application Serial N01 943364; filed August 5, which receivesthefluid pressure supply pipe 2| 30 I936, for Door operating apparatuseandissued so .as to be in communication with a passage 24 as Patent No; 2 0893932 on August L7, 1937. which extendsto a point where it opens into the Inthe accompanying drawings, right hand end of cylinder 6. This passage is Figure 1 is a vertical, central-,- longitudinal, formed by boringf-rom the outside and is nora r ti al; view of the engine with some mally closedv by a screw plug25. parts in elevation and some parts broken away; The-.piston..assemb1y comprises a cylindrical Fi ure: 2 is a some hatsimilar view to that of cup-like member 26 which is threadedlv mounted Figure l with additionalparts in elevation. showonv the reduced. threaded left hand end of piston ing the piston and. connectedpartsat the other rod LI and by which the usual leather piston cups extreme position; and associatedequipment 31- are locked thereon 4O figure: 3' is enlarged; longit di l vertical, against a collar 38 The cup member 26 is formed centralcross-sectional view through the piston as 9 an Internal shoulfiel against which assembly showing the valves in positionfor operf rs??? 3 :3 g gg g gfig fifr62 3x1 38? 323 the plston to the other end of the'cyl ingmember 30. The disc 28 is locked onto a further reduced threaded portion of shaft II by Flgur? 1S slmflar f i g i means of an annular nut 29 which terminates at the engme.w1m the i q ion its free end in an annular seat 29?. The piston they take h P rod II- is provided with a short passage 21, the stroke. towards that end of the cylinder, the peripherythereofextending axially so as to be 50 Valve? bemg then to e el return open at one end tothe interior of cylinder 6 and the plston'to the other at the other end to the space between the end Figure 5 is an enlargedtcross-sectional view of wall of the cup member. 26 and the 'disc 28. the manua ly p a l or positionable. member Within the space between the bushing 30 and 5 which cooperates with the valves onthe piston; the disc 28 is a valve member 31 of the form clearly shown in Figs. '7 and 8. It is of cylindrical cross-section and of cup-shape and provided at the open edge with four extensions 32 which pass through, as is clear from Fig. 6, holes 28* in the disc 28. These holes are larger than the extensions to provide fluid passages. 'The periphery of the valve member 3| is provided with a series of axially extending grooves 3P which to later. Secured to the inner wall of the valve member 3| is a suitable valve disc 34 positioned seat 29.

In the space between the end wall of the cup member 26 and the disc 28 is a movable valve member 35 which is annular in form and has a central aperture to fit around the reduced end of the piston rod II. This annular valve member 35 is provided with an annular groove on the face towards the disc 28 so that when it is seated thereon it seals 01f all of the passages 28*. A spring 36 rests on the annular valve member 35 normally tending to seat it.

Journaled on the end cap 9 is a short shaft 39 whichpasses through a packing 42 and a packing'gland nut 4| and is provided on its external end with a hand operated knob 20. Keyed to the shaft is a cam 40 which may be moved to either of two positions, as is clear from Fig. 4.

The piston rod ll passes through suitable packing 23 in the end cap l0 and a packing gland nut 22. As isv clear from Fig. 6 the rod I9 is longitudinally fluted, as indicatedat l9, which fluting'extends throughout the length thereof.

If it be assumed that theengine is to operate a sliding door on a vehicle such as a subway car. it is mounted adjacent the door by means of brackets I. The bracket I4 is secured to the forward or free end of the door. If a passenger wishes to open the door he applies pressure to it by grasping the usual handle or knob and starts to move it towards opening position. This carries bracket l4 along to the left, compressing spring l6 and causing arm I! to engage the projecting end of rod l9. Further movement of these parts causes rod l9 to move to the left, unseating valve disc 34 from the seat 29 on which it always rests while the door is closed. At the same time valve 35 seats on disc 28 under the action of spring 36 and the pressure fluid acting through passage 21. This opens the. left hand end of cylinder 3 which, prior thereto, was at the same pressure as is present in pipe 2|, to the atmosphere through grooves 30 in the bushing 30, grooves 31 in the valvemember 3|, ports 3| in that member, and to atmosphere through the fiuting 19 in rod l9. Thus the left hand end of the cylinder 6 is open to the atmosphere. The full pressure from pipe 2| is on the right hand end of the piston. so that the motor immediately picks up the door and causes it to open to full position withoutany further exertion on v the part of the passenger. Spring I6 is sufficiently strong to hold the parts in. normally relative position, but not strong. enough to noticeably resist the initial manual movement of the door. The motor picks up the door as soon as the piston rod moves sufliciently with respect to bracket I4 to cause lifrom the atmosphere through the piston rod.

At the same time the extensions 32 cause the valve member 35 to unseat, compressing spring 36. This position of the parts is clearly shown in Fig. 4.

At this time pressure fluid flows from the right hand of the cylinder 6 through passage 21 through the ports 28 and ports 3l grooves 3|, and slots 30 into the left hand end of cylinder 6. The area of the piston at this end, as is apparent from the to engage at the proper time with the annular drawings, is larger than the right end area of the piston so that although the same fluid pressure exists "on both sides of the piston assembly, the

the valve parts stay in the position shown in Fig.

4, and the piston rod and related parts stay in the position shown in Figs. 1 and 3. When in this position the piston remains there having been stopped by the adjacent cylinder head so that no relative movement takes place between the piston and the bracket [4 to actuate the valve. The door will again open when it is again moved a slight distance so that the arm I! engages rod l9, shifting it to the left to cause valve disc 34 to leave the seat 29 permitting valve disc 35 to seat. The engine will then move the door to full open position.

If the door should strike an object in closing it will itself come to a stop, but the piston assembly and piston rod will continue to move, compressing spring I 6 until rod I9 engages the arm IT. .This will cause valve disc 34 to unseat and valve 35 to seat so that the left hand end of the cylinder is open to exhaust and the engine will reverse its movement and move the door to full open position. As before, as it attains full open position, the cam 40 will shift the valve parts to cause the door to immediately begin to close. To hold the door at full open position it is only necessary to turn knob 20 so that cam 40 is swung up to the dotted line position shown in Fig. 4. Under these circumstances, when the piston assembly reaches its extreme movement at the left so that it strikes the shoulder formed by the cap 9 the valves will not shift but will stay in the position shown in Fig. 3 so that the left hand end of the cylinder remains open to exhaust. So long as the pressure is on the right hand side of the piston assembly the engine will hold the therefore, desire to be strictly limited to the dispiston for normally sealing-the passage, and

jclosure' as give for purposes of i'llustraticnbut means at one end of -the cylinder for engaging rather to the'scope of the appended claims.

What'we'olaim is: 1, A fluid pressure engine as described,'-comprising acyli'nder closedat both ends, a piston within said cylinder, ahollow piston rod connected thereto and projecting from one end of the cylinder, said piston having faces of different areas, a connection for continuously supplying fluid pressure to the smaller face of the piston, valve mechanism mounted on the piston, an operating member for the mechanism lying in the hollow piston rod, the hollow piston rod providing an exhaust passage for the end of the cylinder exposed to the larger face of the piston, said operating member actuating the valve mechanism to close 011' the connections between the ends of the cylinder, and means for operating the valve mechanism at the end of the movement of the piston in one direction to interconnect the ends of the cylinder and to close the end in which the larger face of the piston is exposed to exhaust through the hollow piston rod, said last mentioned means being positionable so as not to operate the valve mechanism at the end of the pistcn'stroke to cause the piston to; stop.

2. A pressure fluid operated engine, comprising a cylinder adapted to be connected at one end to a pressure fluid source, a piston in said cylinder, a hollow piston rod connected to said piston and projecting exteriorly. of the cylinder and forming an exhaust passage, a pair of opposed valves mounted on the piston, a passage through the piston controlled by one of said valves, the other controlling the passage through the piston rod, meansmounted in the piston rod and projecting exteriorly thereof for operating said valves simultaneously to close said passage through the piston and to open the' passage through the hollow piston rod so that the piston moves from one end of the cylinder to the other, and means for moving said valves to close the passage through the hollow piston rod and open the passage through the piston at the end of said movement, whereby the piston returns to its initial position and stops.

3. A pressure fluid operated engine comprising a cylinder adapted to be connected at one end to a pressure fluid source, a piston-in said cylinder, a hollow piston rod connected to the piston and projecting exteriorly of the cylinder, a pair of opposed valves mounted on the piston, a passage through the piston controlled by one of said valves, the other controlling the passage through the piston rod, means mounted in the piston rod and projecting exteriorly thereof for operating the valve which controls the passage in the piston rod, a spring cooperating with the valve which controls the passage through the piston for normallysealing the passage, and means positioned to engage and actuate said valves by reason of their travel with the piston.

l. A pressure fluid operated engine comprising a cylinder adapted to be connected at one end to a pressure fluid source, a piston in said cylinder, a hollow piston rod connected to the piston and projecting exteriorly of the cylinder, a pair of opposed, valves mounted on the piston, a passage through the piston controlled by one of said valves, the other controlling the passage through the piston'rod, means mounted in the piston rod and projecting exteriorly thereof for operating the valve which controls the passage in 'the piston rod, a spring cooperating with the valve which controls therpassage through the the valve which controls the passage through the piston rodto cause it-to' close that passage when the piston is at that end of the cylinder.

5. A pressure fluid operated engine comprising a cylinder adapted to be c'onnected at one end to.

trols the passage through the piston for normally sealing the passage, and means interconnecting the valves whereby the seating of one causes the unseating of the other.

6. A pressure fluid operated engine comprising a cylinder adapted to be continuously connected at one end to a pressure fluid source, a piston in said cylinder, a hollow piston rod connected to the piston and projecting exteriorly of the cylinder, a pair of opposed valves mounted on the piston so as to be in opposite ends of the cylinder, a passage through the piston controlled by one of said valves, the other controlling the passage through the piston rod, means mounted in the piston rod and projecting exteriorly thereof for operating the valve which controls the passage in the piston rod, and means at one end of the cylinder for engaging the valve which controls the passage through the piston rod to cause it-to close that passage when the piston is at that opened by the means in the piston rod whereby the piston stops at the end of its return stroke.

'7. A pressure fluid operated engine comprising a cylinder adapted to be connected at one end to a pressure fluid source, a piston in said cylinder, a hollow piston rod connected to the piston and projecting exteriorly of the cylinder, a pair of opposed valves mounted on the piston, a passage through the piston controlled by one of said valves, the other controlling the passage through the piston rod, means mounted in the piston rod and projecting exteriorly thereof for operating the valve which controls the passage in the piston rod, a spring cooperating with the valve which control the passage through the piston for normally sealing the passage, means at one end of the cylinder for engaging the valve which controls the passage through the piston rod to cause it to close that passage when the piston is at that end of the cylinder, and means interconnecting the valves whereby the seating of one causes the unseating of the other.

8. A pressure fluid operated engine comprising a cylinder adapted to be continuously connected at one end to a pressure source, a piston in said cylinder, a hollow piston rod connected to the piston and projecting exteriorly of the cylinder, a pair of Valves mounted on the piston so as to be respectively exposed to the pressure in the cylinder'ends, said piston having a passage therethrough to' be closed by one of said valves, the other ofsaid valves sealing the passage in the piston rod, a spring for normally seating the valve which closes the passage in the piston, means mounted in the piston rod for unseating the valve which seals the passage in the piston rod, means seals the passage in the piston rod when seated in the cylinder positioned to engage the valve being held seated by the pressure in the associated which seals the passage in the piston rod to seat cylinder end' until unseated by the means in the it,'and means interconnecting said valves whereby piston rod.

the seating of the valve which closes vthe passage ROSCOE D. CONIQJIN. in the piston rod unseats the valve which closes PARIS R. FORMAN.

the passage through the piston, the valve which 

